From aa549f923f5e037a459dcd588932db9abfa8c158 Mon Sep 17 00:00:00 2001
From: Kefeng Wang <wangkefeng.wang@huawei.com>
Date: Fri, 6 Sep 2024 10:42:00 +0800
Subject: [PATCH] mm: support poison recovery from do_cow_fault()
Patch series "mm: hwpoison: two more poison recovery".
One more CoW path to support poison recorvery in do_cow_fault(), and the
last copy_user_highpage() user is replaced to copy_mc_user_highpage() from
copy_present_page() during fork to support poison recorvery too.
This patch (of 2):
Like commit a873dfe1032a ("mm, hwpoison: try to recover from copy-on
write faults"), there is another path which could crash because it does
not have recovery code where poison is consumed by the kernel in
do_cow_fault(), a crash calltrace shown below on old kernel, but it
could be happened in the lastest mainline code,
CPU: 7 PID: 3248 Comm: mpi Kdump: loaded Tainted: G OE 5.10.0 #1
pc : copy_page+0xc/0xbc
lr : copy_user_highpage+0x50/0x9c
Call trace:
copy_page+0xc/0xbc
do_cow_fault+0x118/0x2bc
do_fault+0x40/0x1a4
handle_pte_fault+0x154/0x230
__handle_mm_fault+0x1a8/0x38c
handle_mm_fault+0xf0/0x250
do_page_fault+0x184/0x454
do_translation_fault+0xac/0xd4
do_mem_abort+0x44/0xbc
Fix it by using copy_mc_user_highpage() to handle this case and return
VM_FAULT_HWPOISON for cow fault.
[wangkefeng.wang@huawei.com: unlock/put vmf->page, per Miaohe]
Link: https://lkml.kernel.org/r/20240910021541.234300-1-wangkefeng.wang@huawei.com
Link: https://lkml.kernel.org/r/20240906024201.1214712-1-wangkefeng.wang@huawei.com
Link: https://lkml.kernel.org/r/20240906024201.1214712-2-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Jane Chu <jane.chu@oracle.com>
Reviewed-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jiaqi Yan <jiaqiyan@google.com>
Cc: Naoya Horiguchi <nao.horiguchi@gmail.com>
Cc: Tony Luck <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
mm/memory.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/mm/memory.c b/mm/memory.c
index 42674c0748cba..64421ea5a4036 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -5089,10 +5089,14 @@ static vm_fault_t do_cow_fault(struct vm_fault *vmf)
if (ret & VM_FAULT_DONE_COW)
return ret;
- copy_user_highpage(vmf->cow_page, vmf->page, vmf->address, vma);
+ if (copy_mc_user_highpage(vmf->cow_page, vmf->page, vmf->address, vma)) {
+ ret = VM_FAULT_HWPOISON;
+ goto unlock;
+ }
__folio_mark_uptodate(folio);
ret |= finish_fault(vmf);
+unlock:
unlock_page(vmf->page);
put_page(vmf->page);
if (unlikely(ret & (VM_FAULT_ERROR | VM_FAULT_NOPAGE | VM_FAULT_RETRY)))
--
GitLab